# MaplePrimes Posts

## Latest Posts Latest Posts Feed

September 04 2012 by MapleSim 6

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MapleSim has seen a rapid evolution since its inception in 2008 as a multi-domain system-level modeling and simulation environment. Market response has been outstanding: Maplesoft has been working with an expanding list of key industry players such as AISIN AW Co., Ltd. and B&R,  while major customers like

### Bug in implicitplot command

September 03 2012 by Maple

It is the first time  I post a Maple bug in MaplePrimes because I use to submit an SCR.
There is a serious reason to do so. Let us look at the output of
> with(plots):
> implicitplot(sqrt(x^2+y^2)-sqrt((x-4)^2+(y-3)^2) = 5, x = -20 .. 20, y = -20 .. 20,
numpoints = 10^6, thickness = 5, scaling = constrained);
(both in Maple 13 and in Maple 16)

### Logout - but still logged in

September 02 2012 by

Saying 'logout' through the menu bar does not log me out.

I am still logged in (even after leaving the pages).

And I guess, that the according cookie is not properly cleared.
But it should.

### Modelling Flow Inertia in Three Coupled...

August 30 2012 by Maple MapleSim

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1 Introduction

Three tanks are connected with two pipes. Each tank is initially filled to a different level. A valve in each pipe opens, and the liquid levels gradually reach equilibrium. Here, we model the system in MapleSim (including the influence of flow inertia), and also derive and solve the analytical equations in Maple.

### It's a small world

August 27 2012 by Maple

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I would like to pay attention to http://www.ams.org/samplings/feature-column/fc-2012-08 , where a mathematical experiment is applied.

### Maplesoft Application center html view...

August 24 2012 by

Viewing an html application at the application center results in some problems which doesn't allow to view the application in it's html format.

### Missing data at Maplesoft application...

August 24 2012 by

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I had responded to a maplesoft application where data to a .mw worksheet was no longer available and had asked them to find and fix it.

I would have hoped a response would have been put here to mapleprimes to find the data.  Unfotunately the data could not be found and the application was deleted from the application center.

It was Analyzing Data files in Maple - Maple 10 and Maple Net - Nov 7, 2005

Here is the link http://www.maplesoft.com/applications/view.aspx?SID=1685 ...

### Maplesoft application center sorting

August 23 2012 by

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After making a search for applications in the applications center, they are ordered in some crazy unknown way.

They do not appear to be ordered alphabetically by author, nor by title and also they have no date published attached to the searched list.

Searching for all titles by product Maple 16, we find that TEST APPLICATION created July 31 is actually listed behind Robert Lopez's Classroom Tips and Techniques: Slider-Control of Parameters in Numeric...

### MapleSim in direct competition with...

August 18 2012 by

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MapleSim now is in direct competition with Mathematica's System modeller.

I just found that out now, it could have been out for a while but they look similar.  Mathematica is already comparing it with MapleSim and essentially indicating that their modeller is superior.

Let's hear from the Maple crowd.  Is System Modeller better than MapleSim?

### images on surfaces

August 17 2012 by Maple

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Let's see how we can display patterns, or even images, on 3D plot surfaces. Here's a simple example.

The underlying mechanism is the COLOR() component of a POLYGONS(), GRID(), or MESH() piece of a PLOT3D() data structure. (See here, here, and here for some older posts which relate to that.)

The data stored in the MESH() of a 3D plot structure can be a list-of-lists or, more efficient, an Array. The dimensions of that Array are m-by-n-by-3 where m and n are usually the size of the grid of points in the x-y plane (or of points in the two independent parameter spaces). In modern Maple quite a few kinds of 3D plots will produce a GRID() or a MESH() which represent the m-by-n independent data points that can be controlled with the usual grid=[m,n] option.

The plot,color help-page describes how colors may specified (for each x-y point pair to be plotted) using a procedure f(x,y). And that's fine for explicit plots, though there are some subtleties there. What is not documented on that help-page is the possibility of efficiently using an m-by-n-by-3 or an m*n-by-3 datatype=float[8], order=C_order Array of RGB values or am m*n float[8] Vector of hue values to specify the color data. And that's what I've been learning about, by experiment.

A (three-layer, RGB or HSV) color image used by the ImageTools package is also an m-by-n-by-3 Array. And all these Arrays under discussion have m*n*3 entries, and with either some or no manipulation they can be interchanged. I wrote earlier about converting ImageTools image structures to and from 2D density-plots. But there is also an easy way to get a 3D density-plot from an ImageTools image with a single command. That command is ImageTools:-Preview, and it even has a useful options to rescale. The rescaling is often necessary so that the dimensions of the COLOR() Array in the result match the dimensions of the grid in the MESH() Array.

For the first example, producing the banded torus above, we can get the color data directly from a densityplot, without reshaping/manipulating the color Array or using any ImageTools routines. The color data is stored in a m*n Vector of hue values.

But first a quick note: Some plots/plottools commands produce a MESH() with the data in a list-of-lists-of-lists, or a POLYGONS() call on a sequence of listlists (eg. torus in Maple 14). For convenience conversion of the data to a 3-dimensional Array may be done. It's handy to use op to see the contents of the PLOT3D() structure, but a possible catastrophe if a huge listlist gets printed in the Standard GUI.

restart:
with(ImageTools):with(plots):with(plottools):
N:=128:

d:=densityplot((x,y)->frem((x-2*y),1/2),0..1,0..1,
colorstyle=HUE,style=patchnogrid,grid=[N,N]):
#display(d);

c:=indets(d,specfunc(anything,COLOR))[1];

/     [ 1 .. 16384 Vector[column] ]\
|     [ Data Type: float[8]       ]|
c := COLOR|HUE, [ Storage: rectangular      ]|
\     [ Order: C_order            ]/

T:=display(torus([0,0,0],1,2,grid=[N,N]),
style=surface,scaling=constrained,axes=none,
glossiness=0.7,lightmodel=LIGHT3):
#op(T); # Only view the operands in full with Maple 16!

# The following commands both produce the banded torus.

#op(0,T)(MESH(op([1,1..-1],T),c),op([2..-1],T)); # alternate way, M16 only

subsop([1,1]=[op([1,1],T),c][],T);


Most of the examples in this post use the command op or indets extract or replace the various parts of of the strcutures. Perhaps in future there could be an easy mechanism to pass the COLOR() Array directly to the plotting commands, using their color optional parameter.

In the next example we'll use an image file that is bundled with Maple as example data, and we'll use it to cover a sphere. We won't downsize the image, so that it looks sharp and clear (but note that this may make your Standard GUI session act a bit sluggish). Because we're not scaling down the image we must specify a grid=[m,n] size in the plotting command that matches the dimensions of the image. We'll use ImageTools:-Preview as a convenient mechanism to produce both the color Array as well as a 3D densityplot so that we can view the original image. Note that the data portion of the sphere plot structure is an m-by-n-by-3 Array in a MESH() which matches the dimensions of the m-by-n-by-3 Array in the COLOR() portion of the result from ImageTools:-Preview.

restart:
with(ImageTools):with(plots):with(plottools):

p:=Preview(im):

op(1,p);

/                    [ 235 x 354 2-D  Array ]
|                    [ Data Type: float[8]  ]
GRID|0 .. 266, 0 .. 400, [ Storage: rectangular ],
\                    [ Order: C_order       ]

/     [ 235 x 354 x 3 3-D  Array ]\\
|     [ Data Type: float[8]      ]||
COLOR|RGB, [ Storage: rectangular     ]||
\     [ Order: C_order           ]//

q:=plot3d(1, x=0..2*Pi, y=0..Pi, coords=spherical, style=surface,
grid=[235,354]):

display(PLOT3D(MESH(op([1,1],q), op([1,4..-1],p)), op(2..-1,q)),
orientation=[-120,30,160]);


### Two-letter-words quiz for Scrabble playe...

August 13 2012 by Maple 16

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Many years ago, I played Scrabble competitively. One of the first things a beginner tournament player should do is learn the two-letter word list. Recently, I created a worksheet that tests your knowledge of all the valid two-letter words accepted in official tournament play in North America. The worksheet makes extensive use of the StringTools package which has terrific tools for manipulating words.

The worksheet link is below if you'd like to try it out, and I'll...

### Sport with Maple

August 11 2012 by Maple

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Here are 30 all-time men's best 100m  (see http://en.wikipedia.org/wiki/100_metres
and  http://www.alltime-athletics.com/m_100ok.htm )
1      9.58       +0.9    Usain Bolt          16.08.2009

### Trouble with arrows=line option in DEplo...

August 11 2012 by Maple 16

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There is a flaw (bug) in the DEplot routine.  If you load the plottools package before using DEplot with the arrows=line option, the DEplot routine tries to use the line definition from the plottools package.  A worksheet illustrating this problem is below.

### Atlas tool for differential geometry

August 04 2012 by Maple

I would like to pay attention to http://www.scientificcomputing.com/atlas-032408.aspx . It seems to be a powerful tool to research, to teach, and to learn.

### NASA Jet Propulsion Laboratory to Land...

August 03 2012 by Maple MapleSim

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On Monday, August 6 at 1:31 a.m. EDT, NASA will attempt the landing of a new planetary rover, named Curiosity, on the surface of Mars.  The Mars Science Laboratory project is managed by the NASA Jet Propulsion Laboratory (JPL) in Pasadena, California, a world-renowned center for robotic space exploration and advanced science and engineering.  JPL recently began a widespread adoption of Maplesoft technology, and Maplesoft’s products are expected to help JPL save...

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